Automatically fed thread rolling machine



Feb. 10, 1953 J. w. BATCHELDER 2,627,767

AUTOMATICALLY FED THREAD ROLLING MACHINE Filed April 9, 1949 4 Sheets-Sheet l FIG. I

v INVENTOR.

' g James W. Batchelder Horney J. w. BATCHELDER 2,627,767 AUTOMATICALLY FED THREAD ROLLING MACHINE 4 Sheets-Sheet 2 4 m am 1 ir l Fw ww 5 :5 a 1 I A Al 1 Fqb. 10, 1953 Filed April 9, 1949 Feb. 10, 1953 J. w'. BATCHELDER AUTOMATICALLY FED THREAD ROLLING MACHINE 4 Sheets-Sheet 3 Filed April 9, 1949 INVENTOR, James W. Botchelder Aizorney 1953 J. w. BATCHELDER 2,627,767

AUTOMATICALLY FED THREAD ROLLING MACHINE Filed April 9, 1949 4 sheets-sheet 4 69 FIG. l4

INVENTOR 90 James W. Botchelder- FIG. 2| By M Horney Patented Feb. 10,1953

AUTOMATICALLY FED THREAD ROLLING MACHINE James W. Batchelder, Ascutney, Vt; assignor, by

mesne assignments, to The Economy Engineering Company, Willoughby, Ohio, a corporation of Ohio Application April 9, 1949, Serial No. 86,417

This invention relates to thread rolling machines, and particularly to machines adapted for operating either on cylindrical or on tapered Work pieces such as pipe plugs or grease fittings. One object of the invention is to provide a work feed which will operate with either conical or cylindrical work pieces and which will greatly increase the output of the machine. A further object is to provide a thread rolling die system for tapered work in which there will be no more slip between the dies and the work than in ctlindrical work systems. A further object is to providesimple mechanism for varying and controlling the rate of penetration of the dies into the work, and in particular to provide for ready adjustment to a condition giving a large number of work turnsper cycle so that hollow or socketed work pieces may be rolled without distortion or cracking. Additional objects will appear from the following description and claims. p

The invention will now be described with reference to the accompanying drawings, in which Fig. 1 is a vertical section through the machine, taken on line l-l of Fig. 3;

Fig. 2 is a section on line 2-2 of Fig. 1; i

Fig. 3 is a section on line 3-3 of Fig. 1 and the line 3-3 of Fig. 4; V t

Fig. 4 is a section on line 4-4 of Fig. 3

Fig. 5 is a section on line 5-5 of Fig. 3;

Fig. 6 is a view similar to a portion of Fig. 3 but showing the machine set for operation on cylindrical work pieces;

Fig. 7 is an enlarged detail, partly in section on line o F 6;

Fig. 8 is an enlarged detail of parts shown in Fig. 6;

Fig. 9 is a section on line 9-9 of Fig. l;

r Fig. 10 is a diagram illustrating the relationship between the dies and work piece in rolling tapered threads; H

1 Figs. 11, 12 and 1 3 are successive views showing stages in the delivery of a work piece by the feeding mechanism;

Figs. 14, 15 and 16 are sections respectively on lines I l-M, l5-l5 and lB-IG of Figs. 11, 12 and 13; 5

Figs. 17, 18 and 19 are sections respectively on lines Il-IT, iii-l8 and i9-l9 of Figs. 14, 15 and 16;

Fig. 20 is a section on line 20-20 of Fig. 16 and Fig. 21 is a detail section corresponding to a portion of Fig. 14 but with the transfer still moving upwardly.

The machine, is carried on a lower frame I (Fig. 1,) above which is an upper frame 2. The

'5 Claims. (Cl. 80-6) upper and lower frames are joined byside frames 3 (Fig. 5 recessed into them thus preventinginward buckling of the frames] and -2 with consequent binding of the-togglernechanism. Keyed at 4 to theupperand-lower frames are heads v5 and:6 which serve asabutments against-which the toggle mechanism exertsits:pressure., Head 6 has a shaft 1 extending through it,shoulde red at 8 to engage the headonone side and having a hand wheel 9 pinned to. it so as toengage the head on the other. I The shaftcan thereforerotate but cannot movelength 'wise. It-is threaded at I!) into a slide I l which carriesoneoi the dies in a manner to be describedQand serves toadjust the spacing ofthe dies; for.. difierent ,sizes of work pieces. A graduated-pointer l2 cooperates with graduations on the han'dwheel --to.indicate the setting. I To head 5 is pinned at l3 a'yoke l4. A second yoke I5 is pinned at 16 to aslide I -'l carrying the second die. Yokes l4 and. I 5 are pinned together at [8, the latter pin also engagingoneend ofa forked link l9 pinned at 20 to a rocker2l carrying a cam roll 22 which isheld byaspring-23against a toggle operating cam 24. Cam 24 isikeyedto a shaft 25 to which a gear.26.is also keyed. This gear meshes with a second gear 21 ofequal size keyed to a second cam shaft.28.driven by gears. 29 and 30 from a drive, shaft -.3l' extending across the machine. and driven as. will be described. -A tapered collar 32 .(Fig. 9') is also keyed to ,cam shaft 28 and receives acam .33 which. is held in adjusted position by a clamp .34. Thiscam operates the ,workjeeding and positioning mechanism which .will be described ,late'r,' and. because of the 1:1 ratio of gears .25 andjT, is always. in synchronism withcam ffl. j g f i Slides I l and i1; areeachprovidedwitha c'ir. cular track 35 (Figs. 3'and 6) in whicha railjli on a vdieihead 31 is held for a. limiBd swinging O m by a amp pla e 38'. Ea d emea is.p 9 .i d h 3.'(Eisj 1 n whi h a 11 n 4% is m s rew Mv (R --3) sh ldiib collar 42 against longitudinal motion; in a flange on the slide and is threaded througnipinrcjso that by turning the screw, the .an'gle'of the -die heads may be changed from the parallelposition of Fig. 6130 an angular one such-as=islshown in Fig. 3, the angle being determinable .by graduations on the rail as shown in. the latterfig ur e. Each die head has-an outboard. portionldii, be

tween which andthe main part of .the.diej head 'a die 44 is keyedon aspindle 45. One spindle (Fig. 7). is provided with a' flange 46 opposed tof a flange 41 on a universal joint 48, the flanges being held in adjusted position by clamp rings 39, 58 having tightening bolts 5!. The other spindle may be permanently connected to its universal joint 52 by a pin 53. In this way the spindles may be adjusted relative to each other so that the threads on the dies may be brought into registry. In Fig. 6 the spindles are shown parallel and provided with cylindrical dies, while in Fig. 3 the spindles converge and are provided with conical dies.

The universal joints 48 and 52 are each connected by a shaft 55 to universal joints 5% which are slidably keyed at 51 to shafts 58 journaled in a gear box 59. Each shaft 58 carries a gear 68 meshing with a common pinion BI on a drive shaft 62 which may be driven by a motor 63 (Fig. 4) through a belt connection 66. One of the shafts 58 is provided with a sprocket 65 coupled by a chain 56 with a sprocket 6'1 on the toggle drive shaft 3!. box with respect to the die heads a positioning screw 68 may be placed between it and its supporting frame. This is not always necessary but assists in maintaining the relative velocity between the two dies constant throughout a revolution. Due to the use of double universal joints on each spindle drive the speed of each spindle is made substantially constant; although, due to the fact that the angles between each shaft 55 and its respective shaft58 and spindle 45 are not equal when the die head is in angular position (Fig. 3), there is a small variation in speed which can generally be ignored since both heads are similarly affected. If the position of the slide ll be varied, however, the angles and thus the variations in speed will not be the same in the two cases unless the gear box is shifted to bring the drives for the two heads into symmetry, and the positioning screw 68 is desirable for this reason. 7 v

For rolling tapered threads the dies are in the form of cones the diametersof which at any point are integral multiples N1) of the diameter D of the work at that point. The value of N is not critical, but it must bean integer. For practical reasons N usually has the same value for both dies, but it may have different values if the angular velocity of the spindles is made such that the surface speeds of the two dies are the same. If the work is tov be single threaded the dies are multiple threaded with N threads; if the work is n-threaded the dies will have nXN threads. The conical pitch surface formed on the work pieces and the conical pitch surfaces of the two dies lie tangent in a common plane including the axes of the dies, and. have their apexes at the same point. Since the ratio of pitch diameters of a given die and of the work piece is N and therefore the geometrically consequent relationship of the respective apical angles A and B is sin (A/2)=N sin (3/2), for the case of dies of like size and speed, shown in Fig. 10, when the angles are small, it may be taken that the included or apical angle A of the die cones is N times the angle B of the work-cone, and that the included angle C (i. 'e. A+B) between the axes of the dies is (N+1)B, and the angle each spindle is displaced from parallel position is exactly half of this. With these proportions and with the threads on one die adjusted 7 (as by clamp rings 49, 56) so as to be exactly 180 out of phase with those diametrically across the work piece on the other die, work may be introduced between the dies at any time, and when once grasped by the dies will be held by To centralize the gear them firmly in constant axial position as it and the dies rotate. Furthermore, the speed of the surface of the die is, with this arrangement of cones, exactly the same as the surface speed of the work so that there is no slippage.

The dies are apart at the time when the work blank is placed between them, and are then closed to a position which is determinable by the handwheel 9. Gears 29 and 30 are readily removable so that they can be replaced by others having a different ratio. The approach of the dies in one revolution of the work piece can thus be varied to control the rate of the penetration of the dies into the work. It is generally unnecessary to change cam 24 for this purpose. For solid work pieces a relatively high rate of penetration can be used, the threading operation being completed in a relatively few number of work turns; while on hollow work the penetration rate should be slow.

Above the dies are tracks 69 coming from any suitable magazine, the construction of which is not important here. The tracks are shaped to the particular work blank 10, which in this case is shown as a frustum of a cone with chamfered ends. The lower end of the tracks are cut away at it! to receive double-ended escapement blades ll fastened to pins '12 which have at their ends fingers i3 connected by a spring '14 tending to draw the lower ends of the blades within the track. To actuate the blades H a cam bar '15 is mounted on a rocker 16 pivoted at H to a bracket 78. The bracket is adjustably clamped to a dovetail re parallel to the aXis of the work and itself clamped to a dovetail extending crosswise of the work. The latter dovetail is formed on the top of a post 81 sliding in a bearing 82 in the bed and pressed downwardly by a spring 83. A roll 84 on the lower end of the post engages a block 85 held in position by an adjusting screw 86 in one end of a double lever 81, 88. The lever is pivoted to the frame and bears a cam roll 39 riding on cam 33 previously mentioned. The rocker l5, and another one 9 similar to it except that it carries no cam bar, are each formed with a socket or notch 9| to engage the work blank by its ends,-and together form a transfer for taking a blank from the tracks and positioning it between the dies. The two rockers are pressed towards each other by springs 92 so that they grasp the work blank yieldingly. The action of the cam bar on the ends of fingers 73 will be clear from a comparison of Figs. 11, 12 and 13.

The cycle of operations is shown in Figs. 11 to 19, in which Figs. 11, 14 and 17 show the uppermost position of the transfer, Figs. l2, l5 and 13 an intermediate position in its downward travel, and Figs. 13, 16 and. 19 the position where the Work blank has been placed in alignment with the dies and the latter have closed in on them. As the transfer rises,beveled edges 93 (Fig. 21) above sockets ill strike the blank 10 and cause the rockers 6, 58 to spread so that their socketed portions may pass over the ends of the blank and ultimately spring into holding engagement with it as shown in Fig. 15. The transfer then descends and at the same time the dies are separated by the toggle, allowing the finished blank 20' to drop out as in Fig. 12. It should be noted that there is no obstruction, such as a work rest, which prevents the work from dropping out. The lowermost position of the transfer (Fig. 13) brings the blank into the plane of the axes of the dies, a position to which it can be adjusted strikes the left top blade.

accurately by screw 86. At least one finger of the transfer should in this position lie at least in part between the dies so that threads will be formed all the way to the end of the blank. While the transfer holds the blank in this position the dies move in, due to the steady rotation of cam 24. Once the dies have engaged the work blank they hold it so firmly that the transfer can be moved upwardly, its sockets 91 passing over the end of the work with no danger of dislodging it from the dies.

The operation of the escapement is as follows. Starting with a blank resting on the left hand bottom blade and the stack of blanks supported by the right hand top blade (Fig. 19), the transfer rises as soon as the blank it has carried down is grasped firmly by the dies. The cam acts on the left finger 13 to rotate its blades H clockwise sufiiciently to bring the top blade into blocking position under the blanks in the track and the lower blade to a position where it barely supports the blank it is holding. The right hand blades are also rotated clockwise by cam 75, but at a slightly later time. Soon after the left top blade is in blocking position the right hand top blade moves out to release the stack of blanks, which drops (Fig. 17) until its lowest blank By the same motion the right bottom blade is moved over the blank in the escapement to hold it against the upward force exerted by the transfer as it moves against the blank (Fig. 21). The upward stroke of the transfer ends as soon as it has grasped the blanks firmly.

The transfer then starts downwardly, pulling the blank past the left bottom finger, which can yield on account of spring 14. The right hand blades this time move first, rotating counter clockwise to the position of Fig. 18 in which the upper blade supports the blank next to the bottom in the stack, the bottom one being held by the upper blade of the left hand set. These latter blades now rotate counter-clockwise (Fig. 19) so that when the upper blade releases the blank the lower blade catches it.

The toggle cam 24 has its profile so shaped that, taking into account the properties of the linkage it operates, the number of work turns given to work pieces of various depths of thread will be substantially constant. The handwheel 9 is ad- J'usted so that at the end of the toggle stroke the pitch circumference of the dies will be separated by the pitch diameter of the thread. When contact is initially made between the work and blank the outer die surfaces are of course separated by the blank diameter, which is roughly the pitch diameter of the finished work piece. The distance the toggle-carried die moves beyond this is equal to the thread depth. Thus for a fine thread the die would meet the blank later in the cycle than for a coarse thread, and the blank would not have so many turns during actual rolling. The profile of the cam is therefore chosen so that, in combination with the slowing down of the die on account of the normal action of a toggle approaching the end of its stroke, the speed of approach of the die will be reduced sufliciently so that coarse and fine threaded work pieces will have approximately the same number of turns during rolling.

The transfer cam 33 is circumferentially adjustable so that the transfer may be caused to arrive at the plane of the die axes after the completed work piece has been dropped from between the dies, but before the dies again close.

Since coarse threaded pieceshave a less proportion of the cam cycle available for feeding, if the transfer cam is adjusted for coarse work it will also serve for fine. The stroke of the toggle remains constant, being equal to the depth of penetration for the deepest thread that is to be handled plus the necessary clearance for discharge and reception of a work piece, and the toggle cam 24 need not be adjusted when the type of the work piece is changed. If special types of work be encountered, such as hollow screws, the relation between the number of revolutions .of the work and the advance of the dies can be varied by the change gears 29, 30.

For changing from one size of work piece to another it is necessary to change the dies 44, and in order to do this the outboard member 43 must be removed. This member fits in a groove 94 in which it is held by screws 95, and carries a bearing 96 (Fig. 8) for the spindle 45. The bearing may be of the ball, needle or roller type, but for simplicity is here shown as asimple bushing. It is preferably provided with snap rings 91 which attach it permanently to member 43, so that when the latter is removed from'the machine for the purpose of changing dies the bearing will be removed with it and will be protected against dirt and injury. When replaced on the machine the bearing is pressed againstthe die, which rests against a shoulder 98, by a tap bolt 99 acting on a washer I00. g

It is of considerable importance that thework blanks should always be introduced between the dies at the same axial position. When the work blank is headed careful positioning is required so that the heads themselves do not sometimes get between the dies even though the threads run nearly to the shoulder. Also where the work is tapered it will readily be seen that the pitch diameter would vary if the blanks did not all come to the same axial position. To insure the constancy of this axial position the spring 92 under finger 16 is made a little stronger than the corresponding spring under finger 9!]. Finger 16 will thus always come to rest in a constant position against a stop formed by the check nut l9! which holds it against the spring, and finger 96 can shift to take care of small differences in work length. The small end of a tapered blank is preferably chosen as the one to be kept in standard position, since tapered articles such as pipe plugs are generally gauged at this end.

What I claim is:

1. A thread rolling machine having a pair of slides mounted for relative reciprocating movement to and from each other; a die head carried on each of said slides; a spindle carried in each of said die heads, the axes of the spindles being disposed for movement in a common plane upon relative movement of saidslides; a threading die mounted on each spindle; "driving means for rotating the spindles in the same direction; a work blank magazine disposed above the said dies and provided with an escapement mechanism for separating the lowermost work blank from the others; a transfer mechanism for removing the lowermost blank from the magazine and positioning it between the dies with its axis in said common plane, said transfer mechanism including a base below said dies, a pair of opposed fingers pivotally mounted on said base and extending upwardly beyond the said common plane and biased toward each other for grasping a work blank at its ends, at least one of said fingers being disposed between the dies when the transfer has a blank positioned with its axis in said common plane, a work blank and gaging surface provided on said one finger for gaging the axial position of one end of a blank, and means to reciprocate said fingers between said magazine and dies; and slide actuating means for causing said relative reciprocating movement of said slides to effect gripping, penetration and release of a work blank between said dies, said slide actuating means being driven in timed relation with said transfer mechanism to efiect gripping of a blank when said transfer mechanism positions the blank with its axis in said common plane.

2. A thread rolling machine as claimed in claim wherein said fingers, base, and actuating means of the transfer mechanism are disposed to allow free discharge of a finished work blank beneath said dies.

3. A thread rolling machine as described in claim 1, wherein said die heads are adjustably mounted to said slides for varying the relative angular disposition of the spindle axes in said common plane and wherein said base of the transfer mechanism includes a pair of adjustable mountings for adjusting the position of said fingers in two directions parallel to said common plane.

4. In a thread rolling in chine for rolling threads on a conical work blank, a structure as described in claim 1 having conical threaded dies with axes in a common plane and at an angle to each other, adjustable die heads for adjusting the dies relative to each other to set the interaxial angle substantially equal to the sum of the apical angle of the work piece to be threaded and the apical angle of one of the dies, said slides being movable relatively toward each other to bring the apical points of the dies into coincidence in penetrating a work piece, and said transfer mechanism being adjustable parallel to said common plane to position a work blank with its axis passing through the point of coincidence of the apical points of the dies.

5. A thread rolling machine as claimed in claim 1 in which said transfer comprises opposed fingers spring biased toward each other to grasp the work blank at its ends, the finger having the work blank end gaging surface being provided with a stronger spring than the other and with a stop to limit its motion toward the other finger, whereby the work blank will be carried between the dies with one end in a constant position irrespective of minor variations in the lengths of the blanks.

JAMES W. BATCHELDER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,150,249 Avery Aug. 17, 1915 1,286,469 Wilcox Dec. 13, 1918 1,551,591 Thomas Sept. 1, 1925 1,892,631 Crosby et al. Apr. 28, llifll FOREIGN PATENTS Number Country Date 370,773 Great Britain Apr. 14, 1932 537,768 Great Britain July 4, 1941 561,805 Germany Sept. 29, 1932 597,253 Germany Jan. 22, 1933 

